1. Field of the Invention
The present invention relates to the field of grinding and polishing discs which are used in conjunction with grinding and polishing machines to grind and polish the surface of objects. The disc is used in conjunction with well-known grinding and polishing machines having a motor driven shaft which include an exhaust duct or hood for removing dust and debris.
2. Description of the Prior Art
The present inventor is the inventor of issued U.S. Pat. No. 7,377,837 issued on May 27, 2008 for “Grinding or Polishing Arrangement”.
Many forms of grinding and polishing machines and devices have been utilized in the past in a wide variety of applications. In general, all such grinding or polishing machines or devices incorporate a rotating grinding or polishing disc against which a workpiece that is to be ground or polished is positioned. Some of the machines or devices are fully automated; some are hand held devices; and some utilize a manual positioning of a workpiece against the rotating grinding or polishing disc. In general, such grinding or polishing machines in which the workpiece was manually positioned against the rotating grinding or polishing disc were characterized in that they generally comprised a housing in which an electrically powered motor was installed. The motor rotated a vertically oriented shaft and on the remote end of the output shaft there was mounted the grinding or polishing disc. The workpiece to be ground or polished was generally placed against the under side of the disc and the grinding or polishing was commenced on the surface of the workpiece. As the grinding or polishing continued, dust or particulate matter was generated by the abrasion of the grinding or polishing disc on the workpiece. A hood or duct was placed in close relationship to the workpiece and the hood or duct had an opening into which the dust or particulate matter was conducted to be removed to regions spaced from the grinding or polishing machine. In many applications, a vacuum generating pump or device was connected to the remote end of the duct to aid in the removal of the dust or particulate matter.
Such devices had several disadvantages. Since the workpiece was located under the rotating disc to be placed against the underside thereof, the view of the workpiece was often obstructed by the disc. Some prior art discs had a few, narrow radial apertures in regions adjacent the outer periphery of the disc and a small portion of the workpiece was visible therethrough during the grinding or polishing operation. However, very often the workpiece was removed from engagement with the disc at various times in order to inspect the condition of the workpiece and then the workpiece was replaced in the grinding or polishing relationship to the underside of the grinding or polishing disc. Further, the exhaust duct or hood was often not located in the position with respect to the workpiece to allow efficient removal of the dust or particulate matter.
Accordingly, there has long been a need for a grinding or polishing disc in which more of the surface of the workpiece that is being ground or polished may be visible and in which a larger portion of the dust or particulate matter generated during the grinding or polishing operation may be removed.
The previous invention of the present inventor identified and claimed in U.S. Pat. No. 7,377,837 addressed the issue of improving the visibility of the workpiece. However, the workpiece still became very hot and hard to handle. Therefore, in addition to improving the visibility of the workpiece, there is a significant need to provide a cooling vortex to enable the workpiece to be appropriately cooled in addition to being cooled while it is ground and polished.